Many medical procedures require puncturing of the skin, and sometimes underlying tissues, of an animal or human subject. For example, a sharp lancet tip is commonly used to puncture the subject's skin at a lancing site to obtain a sample of blood or other body fluid, as for example in blood glucose monitoring by diabetics and in blood typing and screening applications. A lancing device having a spring-loaded or otherwise energized drive mechanism is often used to carry the lancet along a path of travel, between a retracted or shielded position and an extended position wherein the lancet tip punctures the skin.
Some known lancing devices seek to guide the path of the lancet by positioning a lancet holder between two partial shells or within a tube-shaped carrier. The partial shell method takes two (or more) shells and fastens them together using adhesives, ultrasonic welding, crush fits, snaps, screws, or other fastening methods. Unfortunately, in addition to the dimensional variations (tolerances) inherent to the manufacturing process used to make the shells there is also a tolerance associated with the fastening method. This typically results in a loose guidance of the lancet holder (as too tight of a fit will detrimentally create drag on the lancet holder slowing it down). In order to surmount the issues with the assembled shell method, manufacturers have attempted to mold a ‘tube’ that is monolithic and therefore eliminates the assembly tolerances. However, the tube suffers from the requirement to have draft on the interior surfaces in order to successfully de-mold the part, which can also detrimentally affect lancet guidance.
It is to the provision of a lancing device having an improved guidance mechanism that the present invention is primarily directed.